With Opening Day starter Frankie Montas struggling over the past few weeks, the A’s are searching for a pitcher to fill that role as anchor of the rotation. Chris Bassitt might just be that guy.

Jump-starting an important five-game series with major American League West implications, Bassitt pitched like he’s ready to lead the A’s over the final three weeks of the season. The right-hander blanked the Astros over seven innings in Monday’s 6-0 victory, pushing Oakland’s lead atop the division to 4 1/2 games. Second-place Houston has lost five in a row.

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“We want to start this series hot, which we did. But we want to increase the gap between us and Houston,” Bassitt said. “This is a massive series, and we don’t have a lot of games left. It’s a great opportunity to give us some wiggle room, and tonight was just the start of it.”

Bassitt’s gem marked the just the fourth time an A’s starter has completed seven frames this season. Montas was the last A’s pitcher to do it, also tossing seven scoreless against the Astros on Aug. 8.

“You could see right away [Bassitt] was really excited about the start and was on it right away,” A’s manager Bob Melvin said. “They got a few hits off him, but he didn’t put anybody on, free pass-wise. Good cutter and good curveball. He’s the type of guy you really want on the mound in the first game of a series like that.”

Now 3-2 with a 3.12 ERA overall, Bassitt continues to thrive at the Oakland Coliseum this season. In four home starts, the right-hander has allowed just three runs over 23 2/3 innings (1.14 ERA) with 18 strikeouts.

“He really has been consistent. It’s almost surprising when he’s not,” Melvin said. “He seems to be on it right away. He’s just looking forward to getting another chance. Probably, across the board, he’s as consistent of a starter we’ve had this year.”

Coming off a loss to the Astros at Minute Maid Park on Aug. 29 in what was his shortest outing of the season, Bassitt bounced back in a major way. He allowed just seven hits -- all singles -- to turn in his fifth start of two runs or fewer in eight outings.

Bassitt was done no favors by the postponed games for the A’s due to a positive COVID-19 test. Stewing over his poor outing against the Astros his last time out, Bassitt used the time off to throw extra bullpen sessions with a focus on bettering his offspeed pitches. On Monday, he generated swinging strikes on 41 of his 89 pitches.

“To say the least, I was embarrassed and upset about my preparation going into my last start in Houston,” Bassitt said. “There were back-to-back days where we had protests, and I felt like I was worried about that instead of pitching, and it carried over to the start. The last 10 days, I told myself I had to grind to get back on track.”

Houston’s hitters certainly noticed the sharpness of Bassitt’s pitches.

“He was doing a really good job of going to the two-seamer and the cutter,” Astros third baseman Abraham Toro said. “The ball was going to both sides of the plate. It was hard to sit on one pitch, because the fastball was moving everywhere and the offspeed, he wasn’t throwing it as much, but it was effective today.”

Bassitt’s performance on the mound was only part of an all-around impressive day. He also turned some heads with his defense in the fifth, showing his athleticism to make an over-the-shoulder snag on an infield chopper by George Springer before firing an off-balance throw to Matt Olson at first for the second out.

“I’ve had a couple of texts saying it was pretty good,” Bassitt said. “We’ve had a debate among the pitchers about who the best athlete is, and I hope that ended it. I am over [Mike] Fiers saying he’s a better athlete than me.”

Sean Murphy led the way on offense with a three-RBI night, including a solo shot off Astros starter Cristian Javier in the second that put the A’s ahead, 2-0.

Between Bassitt’s deep outing and quick work by relievers Jake Diekman and Lou Trivino -- with Trivino turning in a three-pitch ninth -- the A’s are in good shape for Tuesday’s doubleheader, the first of four twin bills they will play over the next 20 days.

“I didn’t have to use [closer] Liam [Hendriks]. Limited pitches for Diekman and limited pitches for Lou,” Melvin said. “Going into a doubleheader tomorrow, that’s about as good as you can ask as far as bullpen availability.”